The invention concerns an extension guide for a drawer including a carcass rail to be fixed to a furniture carcass, a drawer rail to be fixed to the drawer, and a central rail mounted movably between the carcass rail and the drawer rail. At least one running carriage having at least one rolling body is mounted displaceably between the central rail and the drawer rail, and the at least one rolling body runs on at least one support profile of the central rail.
Such extension guides belong to the state of the art and are described for example in German Utility Model specification DE 20 2009 003 883 U1. In that case, the central rail is shaped so that, viewed in cross-section, it has at both sides two support profiles on which the ball bearings of two running carriages run. In that case, the purpose of the support profiles is to prevent the running carriages from lifting off the central rail and/or to reduce the tilting play which generally occurs in the case of extension guides without a support profile and which occurs due to the relative clearance between the rails and the at least one running carriage.
That central rail therefore differs from the shape which is usually found to involve of a U-profile having two vertical legs and a horizontal bar which connects the two vertical legs, in which the deviation involves in particular the bend edges between the two vertical legs and the horizontal bar.
A disadvantage in that respect is that production of the central rail and thus the entire extension guide is highly complicated and cost-intensive in comparison with the standard form, by virtue of that specific configuration which requires a special bending process.